API PUBL 959

Description

This study evaluates the temper embrittlement characteristics of Cr-Mo pressure vessel steels. The steels are designated A387 in Part 4 of the ASTM Book of Standards. Most of the samples studied were of Grade 22 (2-1/4 – 1Mo) and a few samples of Grades 11 and 21 were also included, (1-1/4 Cr – ½Mo, 3Cr – 1Mo). The 64 samples studied represented a wide range of commercially available steel, including qualification welds in 1-inch and 6-inch steel plate, large nozzle cut-outs, and randomly-shaped pieces of forging material. These materials received heat treatment typical of hydro-treater reactor fabrication. The objective of this program was to characterize typical commercial reactor steels and weldments in terms of toughness and other physical properties prior to being placed in service and the changes anticipated in toughness due to long-time service at elevated temperatures. It is important to note that the materials studied were typical of commercial production and fabrication up